Ion implantation is a standard technique for introducing conductivity-altering impurities into semiconductor wafers. A desired impurity material is ionized in an ion source, the ions are accelerated to form an ion beam of prescribed energy, and the ion beam is directed at the surface of the wafer. The energetic ions in the beam penetrate into the bulk of the semiconductor material and are embedded into the crystalline lattice of the semiconductor material.
An ion implanter includes an ion source for converting a gas or a solid material into a well-defined ion beam. The ion beam typically is mass analyzed to eliminate undesired ion species, accelerated to a desired energy, and implanted into a target. The ion beam may be distributed over the target area by electrostatic or magnetic beam scanning, by target movement, or by a combination of beam scanning and target movement. The ion beam may be a spot beam or a ribbon beam having a long dimension and a short dimension.
Many components of an ion implanter are operated under vacuum in a vacuum chamber. Besides allowing ion implantation to occur, a vacuum may be desirable during ion implantation to reduce contaminant particles that could transfer to a workpiece. Uncontrolled leaks in these vacuum chambers used for ion implantation can cause an ion beam to scatter and allow particles to enter the vacuum chamber.
If two vacuum chambers need to be linked, seals are required to keep both chambers at vacuum. A previous method for forming such a seal is, for example, using a wedge-shaped seal design with a face seal on both sides of the wedge. This method may provide compliance for linear misalignments, but provides very little compliance for angular misalignments. Another example is the use of flexible bellows, but this is typically difficult to install and is cost-prohibitive for larger openings. Yet another example is the use of a piston seal on one end of the seal and a face seal on the other end. However, this particular method provides very little angular compliance due to o-ring compression and usually requires alignment.
Accordingly, there is a need in the art for a new and improved apparatus to seal between vacuum chambers.